Objectives to identify the prevalence, and describe the management of, neutropenia throughout the chemotherapy treatment among women with breast cancer. Methods observational study, cycles of chemotherapy. 116 neutropenic events were recorded, and 63.3% of the patients presented neutropenia at some point of their treatment, 46.5% of these presenting grade II. The management used was temporary suspension between the cycles and the mean number of delays was 6 days. The study was prospective and longitudinal, where the evaluation of the hematological toxicities was undertaken at each cycle of chemotherapy, whether neoadjuvant or adjuvant. Results 79 women were included, who received 572 cycles. However, the reasons for the suspensions were the lack of a space in the chemotherapy center, followed by neutropenia. Conclusion neutropenia is one of the most common and serious adverse events observed during the chemotherapy. Nursing must invest in research regarding this adverse event and in management strategies for organizing the public health system, so as to offer quality care.